Materials Literature
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Abstract The α and β relaxations of a variety of polyethylenes have been extensively studied using lowfrequency dynamic mechanical methods. The main focus of this work has been both the control and the quantitative measurement of the key structural factors that describe semicrystalline polymer systems. The structural…
In this present work, a continuation of others, there is studied the variation of pH, as likewise the concentration of the ions Ca (II), Mg (II), SO4 (II) and Cl (I) of artificial sea water (ASTM D 1141-75) in which there have been submerged the series of test specimens of mortar (1: 3) made with an industrial Portlan…
This study covers point relating to capacity of aggregates to superficially retain part of the water used in mortar and concrete mixtures. It relates this property with the real characteristics of the aggregates. The superficial retention capacity is a decisive factor to determine dosage of mortar and concrete mixture…
Almost all the studies carried out on cements with the addition of flying ash refer to their characteristics and behaviours in pastes, mortars and concretes, always in relation with Portland cement. This time, there has been developed an experimental work oriented to relate between themselves the cements with addition…
In this work there is studied, in the frst place a certain manner of constructing which was practiced by the ancient inhabitants of the Iberian Peninsula, and which was seen by the Romans on their arrival. This form of constructing consisted in making walls of earth called "formaceos", and which are the basis of a rud…
Abstract Alternating and random copolymers of ethyl α‐cyanocinnamate and vinyl acetate were studied. Infrared, 1 H, and 13 C spectra of the copolymers are discussed by comparison with a model compounds, poly(vinyl acetate), and various copolymers. The decomposition temperature and T g of copolymers of various composit…
The spinel systems with has been studied by means of impedance measurement, differential thermal analysis, and x‐ray diffraction analysis. The ionic conductivity increases and the activation energy for conduction decreases with increasing within the solid solution range, in , in , and in . The highest conductivity is…
A preheater with fluidized bed is planned on a pilot scale, capable of being fitted to a rotatory furnace, also of a pilot nature, for the manufacture of Portland clinker. With this it is intended to design a system of dynamic simulation of clinkerization, to obtain clinker of similar characteristics to those which ar…
Abstract The dependence of the physical properties of sulfur vulcanizates of diene rubbers on network structure is reviewed and the influence of degree of crosslinking, crosslink structure, and main-chain modification are discussed. In polyisoprenes, these are determined, in practice, by the balance between three comp…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSome chemical and analytical aspects of polysaccharide modifications. III. Formation of branched-chain, soluble chitosan derivativesMansur Yalpani and Laurance D. HallCite this: Macromolecules 1984, 17, 3, 272–281Publication Date (Print):March 1, 1984Publication History Publ…
Abstract Based on the extended Hückel molecular orbital calculations, the relation between the anisotropy of the band structure and the arrangement of the organic molecules is investigated for two organic donors, tetrathiafulvalene (TTF) and bis(ethylenedithio)tetrathiafulvalene (BEDT–TTF). The intermolecular overlaps…
Magnetization, magnetic susceptibility, optical microscopy, X-ray diffraction and neutron diffraction measurements have been made on a quenched sample of Ni2MnGa. Room-temperature neutron diffraction patterns indicate a highly ordered Heusler alloy, L21 type, structure. The alloy is ferromagnetic with a Curie temperat…
For pt.III see ibid., vol.16, no.11, p.2087 (1983). The well-known relations for the total amount W of material that diffuses in time t into or out of a semi-infinite solid when the surface y=0 is held at some constant concentration, are to be multiplied by a factor (1+ epsilon 2 U) when the solid contains dislocation…
The temperature dependence of the low-frequency light scattering spectrum of quartz has been studied in the vicinity of the alpha - beta transition and in the incommensurate phase. New excitations have been observed in the range 0-20 cm -1 .
From an experimental determination of the temperature and pressure dependence of the R 25 soft-mode frequency in RbCaF 3 , KZnF 3 and CsCaF 3 , it is shown that the overall temperature-dependent shift of the soft mode is mainly due to the self-energy (the purely anharmonic effect) whereas the quasi-harmonic contributi…
The defect-induced one-phonon infrared absorption in natural diamond can be divided into a number of overlapping components. The computational method of extracting the spectral shapes of these contributions is described. The A and B components are associated with nitrogen defects. The A defect is a pair of substitutio…
The basic methods used in the computer simulation of the atomic structure and structural changes of defects in metals?molecular dynamics, variational procedures, and the lattice statics method?are briefly reviewed. There is a discussion of some new interatomic potentials, in particular, potentials which incorporate th…
The general principles of the polymerisation filling of polyalkenes and various other polymers have been examined. Physical and chemical methods for activating mineral and organic fillers, which lead to the production on their surface of active centres initiating polymerisation processes, have been discussed. The kine…
The polymerisation of solid monomers deformed under high pressure has been examined. The anomalously high reactivity of the substances under these conditions, and the reasons for it, have been discussed. The possibilities provided by the methods of formal kinetics for the description and study of the mechanism of poly…
The results of the study of the radical polymerisation of vinyl monomers taking place under non-isothermal conditions, namely under purely adiabatic conditions, with transfer of heat to the surrounding medium, under the conditions of propagation of the polymer front, and the influence of hydrodynamics on the kinetics…